Laurie and Debbie say:
A major science story on the consequences of what we believed was healthy eating has been simultaneously buried and distorted for the press by the National Institutes of Health, to a degree that even the two us find astonishing.
Here’s the short version from Sandy:
It was named the Women’s Health Initiative (WHI) Dietary Modification Trial. A total of 48,835 postmenopausal women (the age most associated the risk for developing heart disease and cancers) were randomly assigned (with each group well matched) to either their regular unrestricted diet or to a “healthy” diet that was low-fat (20% fat) and high fiber, with at least 5 servings of fruits and vegetables, and 6 servings of grains a day.
More than 8 years later, there was no difference in the incidences of breast cancer, colon cancer, heart attacks or strokes among those who ate “healthy” and those who ate whatever they pleased.
We’ll go a little further into the science in a minute, but first let’s look at how this has been reported.
First of all, you know that if they had found (as they expected to), clearcut positive results from the “healthy” diets, you wouldn’t have been able to walk down the street or turn on a radio or television without hearing endlessly about it. But since they found out we can eat what we want, here’s what happened.
The Women’s Health Initiative is a program of the U.S. government’s National Institutes of Health. Its own site has issued exactly one press release: “Low-Fat Dietary Pattern May Lower Risk of Ovarian Cancer — The WHI Dietary Modification Trial.” They are not, in fact, honest about the statistical significance of the findings, although the Journal of the National Cancer Institute, which takes its information, and its spin, from the WHI, does admit “the overall ovarian cancer hazard ratio (HR) was not statistically significant.”
The media gets its science news largely from press releases and journal articles. Since this is all that the study’s creators are releasing, the overwhelming silence is somewhat less surprising.
Nonetheless, the news should be all over the headlines, based on the Journal of the American Medical Association articles which Sandy mentions. The only conclusion we can draw is no one likes these answers, so no one reports the news. What we don’t understand is why the fast food restaurants and prepared food companies aren’t using these figures as advertisements!
Here are some of the hard numbers, and some explanations.
Ã¢â‚¬Å“a dietary intervention that reduced total fat intake and increased intakes of vegetables, fruits, and grains did not significantly reduce the risk of CHD, stroke, or CVD in postmenopausal women.Ã¢â‚¬Â
Ã¢â‚¬Å“We found no evidence that lower intake of total fat or specific major types of fat was associated with a decreased risk of breast cancer.Ã¢â‚¬Â In fact, women who had eaten the lowest fat diets before the study began (i.e, probably before menopause) had slightly higher risks for breast cancer than women with the highest-fat diets; the women who with the biggest reductions in fat in their diets were at the highest risks for breast cancer. (None of these numbers were statistically significant, however.)
Ã¢â‚¬Å“A low-fat dietary pattern intervention did not reduce the risk of colorectal cancer in postmenopausal women during 8.1 years of follow-up.Ã¢â‚¬Â
What’s more, there were no significant changes in the weight of either group.
In her second post, Sandy makes a couple of important points.
Other things that made no difference in risks for the invasive cancers between the dieters and control group included: diabetes; dietary fats, grains, or fruits and vegetables intake (in separate analyses); physical activity (from less than 1.5 to more than 14.8 METS/week); and BMI. Yes, despite all of the fears about body weights, incidences of invasive cancers were not significantly different among women who were fat (in the Ã¢â‚¬Å“overweight,Ã¢â‚¬Â Ã¢â‚¬Å“obeseÃ¢â‚¬Â and even Ã¢â‚¬Å“morbidly obeseÃ¢â‚¬Â medical categories).
One of Junk Food Science’s particularly important qualities is Sandy’s ability to explain scientific and statistical concepts clearly. Speaking about the slightly increased numbers on liver cancer, she says:
It is important to remember that relative risks or odds are not the same as actual incidences of disease; so, that 130% higher risk of liver cancer obviously does not mean that 130% of women got that cancer. In actuality, the total incidences of liver cancer was 0.0368%, with only 3 actual cases difference between the 48,835 women. As the researchers noted, it’s not statistically greater than a random toss of the dice.
Of course, the study only tracked women, and only focused on the post-menopausal period. There are more studies to be done. In the meantime, however, this is an astonishingly strong brick in the structure of “be relaxed about what you eat and eat a wide variety of what tastes good to you.”
Thanks to fattest for pointing this out before we got to it!